Background. Lichen planus (LP) is a T-cell mediated autoimmune disorder of unknown aetiology that affects the skin, nails, oral and genital mucous membranes. Conventionally, oral LP (OLP) is diagnosed through clinical assessment and histopathological confirmation by oral biopsy.Aim. To explore the use of time-resolved fluorescence spectroscopy (TRFS) to detect fluorescence lifetime changes between lesional OLP and perilesional normal mucosa.Methods. In this pilot study, measurements of lesional and perilesional buccal and mouth floor mucosa were conducted in vivo with a TRFS system. Histopathological findings were consistent with OLP in 8 out of 10 patients biopsied. Two patients with histopathological diagnoses of frictional hyperkeratosis and oral candidiasis, respectively, were excluded from the study.Results. Our preliminary data show that lifetime values in the 360-560 nm spectral range indicate a significant differentiation between normal and diseased tissue. In contrast to the standard oral biopsy procedure, this technique is noninvasive, painless, time-efficient and safe.Conclusions. Future studies are needed to better elucidate the diagnostic capability of TRFS and to further explore the sources of fluorescence contrast. This pilot study suggests that, based on fluorescence lifetime parameters, TRFS is a very promising technology for the development of a novel OLP diagnostic technique.